Year 8 Extension Science: Chemistry Topic Test Revision

Chapter 1: Scientific Inquiry

1.1 Hazards

  • Understand potential hazards in laboratory settings.
  • Importance of safety measures and protocols.

1.2 Design Experiments

  • Key steps to designing a scientific experiment.
    • Identifying the problem.
    • Developing a method to test the hypothesis.

1.3 Writing Formal Reports

  • Structure of a formal report:
    • Title page.
    • Introduction (hypothesis, objectives).
    • Methodology.
    • Results (data representation).
    • Conclusion.
1.3.1 Dependent, Independent, and Controlled Variables
  • Independent Variable: The variable you change.
  • Dependent Variable: The outcome you measure.
  • Controlled Variables: Factors kept constant to ensure valid results.
1.3.2 Formulating Hypothesis
  • A hypothesis is an educated guess about the outcome of an experiment.
  • Should be testable and falsifiable.
1.3.3 Tables and Graphs
  • Importance of organizing data.
  • Graphing results to visualize relationships between variables.
1.3.4 Calculate Averages
  • Process of calculating mean, median, and mode of data sets.

Chapter 4: Chemical Elements

4.1 Properties of Matter

  • Matter: Anything that has mass and volume.
  • Two necessary criteria for matter:
    • Occupies space.
    • Has mass.
  • Physical Properties: Characteristics observable without changing composition.
  • Chemical Properties: Characteristics observed during a chemical reaction.
  • Density: Mass/Volume. Higher density = sinks; lower density = floats.

4.2 The Particle Model

  • Explains the structure and behavior of matter.
  • States of matter: solid, liquid, gas based on particle arrangement and movement.

4.3 The Particle Model and Properties of Matter

  • Definitions:
    • Tensile Strength: Resistance to breaking under tension.
    • Compression Strength: Ability to withstand axial loads.
    • Hard and Brittle: Hard materials resist deformation; brittle materials break or shatter under stress.
    • Viscosity: Resistance of a liquid to flow.
    • Compressibility: Ability of a substance to decrease in volume under pressure.
    • Density: Calculated as mass/volume.

4.4 Effects of Heat

  • Heating and Expansion: How heat causes substances to expand at the particle level.
  • Application of the particle model to explain thermal expansion.

4.5 Atoms, Elements, and the Periodic Table

  • Atoms: Basic units of matter.
  • Elements: Substances that consist of only one type of atom.
  • Properties of Metals vs. Non-Metals:
    • Metals: Conduct electricity, malleable, ductile.
    • Non-Metals: Insulate, brittle in solid form.
  • First 20 Elements of Periodic Table: Symbols need to be memorized.
  • Types of elements:
    • Monatomic: Single atoms (e.g., Noble Gases).
    • Molecular: Molecules made of nonmetals (e.g., O2, H2).
    • Crystal Lattice: Regular arrangement of atoms (e.g., NaCl).

4.6 Molecules and Compounds

  • Molecular Elements: Consist of one type of atom.
  • Molecular Compounds: Consist of molecules made from different elements.
  • Mixtures: Combination of two or more substances not chemically bonded.
  • Ability to identify each from diagrams.

Chapter 5: Physical and Chemical Change

5.1 Physical Change

  • Definition: Changes affecting one or more physical properties of a substance without altering its chemical composition.
  • Example: Changes in states of H2O (ice, liquid water, steam).
  • Explain kinetic energy and particle movement during state changes.

5.2 Chemical Change

  • Definition: A process in which substances undergo chemical transformations into different substances.
  • Differences from physical changes include formation of new substances.
  • Signs of Chemical Change: Color change, temperature change, gas production, precipitates.

5.3 Chemical Reactions

  • Reactants: Starting substances in a reaction.
  • Products: Substances formed from the reaction.
  • Understanding and writing word equations and simple chemical equations.

5.4 Speeding Up Reactions

  • Conditions for reactions to occur:
    • Particles must collide with sufficient energy.
  • Heat provides energy that increases particle movement.
  • Factors that can change reaction rate include:
    • Size of Particle: Smaller particles react faster due to higher surface area.
    • Temperature: Higher temperature increases kinetic energy and rate of reactions.
    • Concentration: Higher concentration increases reaction likelihood.
    • Catalysts: Agents that speed up reactions without being consumed in the process.